[Sets] Update SetManagerTest to the single Twig composer-based set

[TomasVotruba]

Follow-up to #8292, fixes the 4 SetManagerTest failures on main.

rectorphp/rector-symfony#1010 is merged, so TwigSetProvider now registers only its composer-based trigger. The per-version Twig sets were dropped there because every rule in them is already in config/sets/twig/composer-based.php, bound to the exact twig/twig version it needs — so a Twig 2.0 project still gets exactly the rules it got before, just from one set instead of three.

-        $this->assertCount(8, $twigComposerTriggeredSet);
+        $this->assertCount(1, $twigComposerTriggeredSet);

-        yield [
-            __DIR__ . '/Fixture/project-twig-20',
-            [realpath(TwigSetList::COMPOSER_BASED), realpath(TwigSetList::TWIG_20)],
-        ];
+        yield [__DIR__ . '/Fixture/project-twig-20', [realpath(TwigSetList::COMPOSER_BASED)]];

tests/Set green: 12 tests, 15 assertions.

[TomasVotruba]

Folded into #8293, so that PR is green on its own.